I try to be honest, but it can be rather subjective. More than 50% with at least an inch; is there an app for that? If my snowboard or snow stake spot is bare, that's an argument against, although there are exceptions to every rule. If the wind strength and direction scoured my entire property bare, but every where else is buried...calling that 0 snowcover is inaccurate. If I have an eight foot deep drift remaining while the rest of planet earth is bare, averaging it out against the rest of Tara and calling an average of an inch is BS too.
It's a judgement call and no one who wasn't there can dispute it with any certainty. For reference, we haven't actually had any accumulating snow here since 1978.